From the expression of (REF ), it is clear that the lower index of the \(W\)  tensor has the \(rs\)  component representing the entanglement between a pair of elementary regions \({A_r}\)  and \({A_s}\) , while the upper index has no \(rs\)  component. Therefore, the \(W\)  tensor is exactly playing the role of a \(disentangler\)  (of course, it also plays the role of the \(coarse\) -\(grainer\)  at the same time. A preliminary discussion of this issue can be seen in [1]}, [2]}), because it is such a unitary operation that just converts the state of two entangled blocks in the previous layer into a state of a block without internal entanglement. This process of disentanglement can be intuitively understood as removing the contribution of the inner threads that represent the shorter range entanglement! This process is carried out successively, exactly in line with the idea of MERA-like tensor network, that is, the effect of short-range entanglement is successively removed and only the effect of long-range entanglement is finally focused on [3]}, [4]}, [5]}, [6]}.
